Do you know what the difference between In-Laws and Out-Laws is?
Out-Laws are
wanted. I can sympatize Devan. I've got a few BIL's that really make it a point that they don't want to have anything to do with my wife's family, until they need money.
I have one BIL that sounds so much like yours. Well educated, but I don't think that has anything to do with it. He just always has the need to be "right". I've known him for 19 years and so many in the family have to walk on eggshells around him. In the last 8 years or so I've found that if I don't disagree with him we get along fine. I try to find a topic of discussion that he can "educate" me on. He eats that stuff up like the icecream that fatty eats.
I do it for his wife that i adore. He's much better with the family but still rides his wife over every little thing. It makes me want to puke.
Being under the same roof must really suck. My wife's brother and his 3 young boys moved in with her in her 2 bedroom apartment and stayed for years. He has never thanked her for supporting him and the nephews for that time. Never, but he still acts like he's better and smarter than the rest of the family and siblings. (He just lost his million dollar plus home and the bride and I had a good chuckle. Even though that's probably wrong.)
Don't even get me started about my sister's husdand. Our mom took years to die from cancer and that A-H never even called never mind visit. He sleeps to 2 PM, takes a long nap, makes my sister cook him dinner about 10 PM , then goes out drinking all night.
Had to share that you are not alone. You need to remember something important. It's your house, you're the boss, and he's your guest. Don't let him piss you off. He should be kissing your feet and buying you a nice box of cigars once a week. Maybe pay some rent too.
You can pick your ass, you can pick your nose, but you can't pick your family.
Chin up, smile, and start leaving the apartment listings out on the table.
Stay strong.